1. Field of Endeavor
The present invention relates to devices, systems, and processes useful for receiving and radiating radio frequencies from below 1 Megahertz (MHz) continuously through 200 MHz using a single antenna without the need for adjusting or tuning its physical or electrical length when changing the frequency of the transceiver for the desired band of interest.
2. Brief Description of the Related Art
Communication antennas are designed to be used on a particular frequency band or bands of interest. An antenna is designed to be a physical or electrical size, proven to be a ¼ to ½ wavelength or a multiple of such wavelength, in order to resonate on that band of interest in order to provide a good voltage standing wave ratio (VSWR) match to the transceiver for efficient operation. The impedance of current radio transmitters are made to match an industrial standard of 50 ohms. The formula for determining the physical size of a ½ wave dipole is calculated by 468/f, where f is in Megahertz (MHz) and the result is length in feet. For an example, the size of a ½ wave dipole tuned for the 80 meter band which is approximately 3.5 MHz would be calculated as 468/3.5=133 feet. This is a very large antenna. The lower the band of interest the larger the antenna becomes. The higher the frequency the smaller the antenna length becomes. For an example, the size of a ½ wave dipole tuned for the 2 meter band which is approximately 142 MHz would be calculated as 468/144=3.25 feet.
Current antenna designs made to operate on more than one band of frequencies are called multiband antennas. The common ones that are available are limited to 2 to 6 bands and are very narrow in bandwidth. Some designs use complicated Trap coils for each band which trap or impede certain sections of antennas elements to allow for multiband operations. These traps are fragile and have losses and are prone to overpower burnout and damage over time from weather. These are very complicated to assemble and tune as any adjustment made on one band will affect the other. These antennas require a ground radial system or counter poise if used in a vertical configuration.
Other antennas used for multiband operation use a balun transformer for impedance matching, which is prone to burn out and limits the amount of power that can be fed to the antenna from a transmitter. Log Periodic Yagi or beam antennas for multiband use are further limited due to size for the same reasons as just mentioned. Many other antennas that will not tune properly can be aided with an external antenna matching units which are expensive and time consuming to use every time the user needs to switch bands. There are automatic tuning units, or ATU, which require another power source to operate and get very expensive for higher power handling requirements.
All of these antennas mentioned above are subject to capacitive loading from nearby objects. They are affected by proximity to ground, trees, homes; even the feed line can greatly influence their resonance affecting the performance and VSWR readings matching the transceivers impedance.
Thus, there remains a need for antennae which suffer less from these deficiencies.